U.S. application Ser. No. 14/139,550, filed Dec. 23, 2013, and U.S. Provisional Application No. 61/740,557, filed Dec. 21, 2012, are incorporated herein by reference in their entirety.
Heavy machinery, such as construction equipment, agricultural machines, and heating, ventilation, and air condition (HVAC) units typically use ball bearings to reduce the amount of friction between moving parts. Generally, a ball bearing assembly, or bearing, includes an outer race, an inner race, and a plurality of ball bearings disposed between and engaging the inner and outer races to permit free rotation therebetween. One common use of this type of bearing is found in a squirrel cage blower. The blower is supported on a rotating shaft which is in turn supported by bearings within a blower housing. Support arms extend from the blower housing to a bearing housing at the end of the shaft. Normal wear and exposure to the elements requires eventual replacement of the bearings. During use, however, bearings tend to become firmly seated or rusted on the shaft requiring considerable force to remove them.
Various methods have been used to remove bearings seated on the shaft in this manner, and each of these methods has its drawbacks. The bearing housing typically makes prying the bearing from the outside unsuccessful, and reaching inside the blower housing with tools to apply outward force is difficult given the limited space and placement of the support arms. Another method includes reaching inside the blower housing with a torch to heat the bearing in an effort to unseat it, and then apply the outward force. In cases that are more difficult, the torch is used to cut the bearing from the shaft. Each of these methods may result in damage to the shaft or the surrounding housing. In addition, these methods could result in safety concerns. In any case, they are labor intensive and time consuming, and thus expensive. Moreover, if an asymmetrical force is applied to the bearing during removal, extraction may become even more difficult.
Another technique used to remove a bearing or the like from a shaft uses a bearing puller. Reference in this regard, Shevada, U.S. Pat. No. 4,372,024 discloses a split pusher portion positioned behind the bearing and a split puller portion positioned outside the housing. As seen in FIG. 1 of the patent, pull bolts 20 are positioned in opposing slots 19 and 22 of the puller and pusher portions, respectively, and a central bolt 21 positioned against the shaft is advanced to urge the bearing from the housing. The pusher portion is assembled inside the blower housing using four bolts, but nothing appears to prevent lateral movement of pull bolts 20 in the slots 19 and 22. If a bearing was firmly seated on the shaft, it seems possible that as the pressure from advancing central bolt 21 increases, pull bolts 20 could slide laterally outward in slot 22, possibly disengaging therefrom.
When the end of the shaft is not accessible because a hub surrounds the bearing, another type of bearing pusher is sometimes used. Reference in this regard, Straut, U.S. Pat. No. 5,509,186 discloses affixing a split anchor block portion rearward of a split pusher block behind the bearing and inside the blower housing. As seen in FIG. 1 of the patent, pushing members, or bolts 16, are advanced through the anchor block portion 15 applying pressure against the pushing block 19 for pushing the bearing off the shaft. According to FIGS. 3 and 4, the ends of bolts 16 are sized and shaped to engage the pushing block 19 at sockets 46 to prevent lateral movement thereof. Because the pressure is applied at sockets 46, it seems likely that the bearing will be subjected to asymmetrical forces as the top bolt is advanced and then the bottom bolt is advanced. This torsion of the bearing could actually make it more difficult to remove from the shaft. Another drawback of this bearing pusher is that it must be assembled and used inside the blower housing where space and accessibility are limited.
Accordingly, what is sought is a bearing removal tool which overcomes at least one of the problems, shortcomings or disadvantages set forth above.